Relativistic independence bounds nonlocality

TL;DR

This paper introduces the concept of relativistic independence, a principle that constrains nonlocal correlations by ensuring local uncertainty relations, and shows that stronger-than-quantum correlations violate this principle.

Contribution

It establishes relativistic independence as a new principle that characterizes quantum correlations and rules out stronger nonlocal correlations beyond quantum mechanics.

Findings

Stronger-than-quantum correlations violate relativistic independence.

Relativistic independence links local uncertainty to nonlocal correlations.

Quantum correlations satisfy the proposed locality condition.

Abstract

If Nature allowed nonlocal correlations other than those predicted by quantum mechanics, would that contradict some physical principle? Various approaches have been put forward in the past two decades in an attempt to single out quantum nonlocality. However, none of them can explain the set of quantum correlations arising in the simplest scenarios. Here it is shown that generalized uncertainty relations, as well as a specific notion of locality give rise to both familiar and new characterizations of quantum correlations. In particular, we identify a condition, relativistic independence, which states that uncertainty relations are local in the sense that they cannot be influenced by other experimenters' choices of measuring instruments. We prove that theories with nonlocal correlations stronger than the quantum ones do not satisfy this notion of locality and therefore they either violate the underlying generalized uncertainty relations or allow experimenters to nonlocally tamper with the uncertainty relations of their peers.